Mar 01, 2003 dale walkers modified dynaco mk iii nice work. Dynaco mkiii mk iii mk3 mk 3 tube amplfier restoration kit. But you may have to alter the voltage divider resistors in the bias supply for the proper voltage. So shannon, with poseidon boards you can mod mkiis and drive them with different tubes. Here is a kit to electrically restore your dynaco mk iii to like new condition. Hard to find parts including dynakit original dropin replacement components typically ship within 24 hours of ordering. The other benefit of the dynaco is that at 60 watts, i could use them with a pair of paradigm studio 100s i have in storage if i didnt like them better than the fisher. I am happy with the product quality and the performance of the vta driver boards. In the march 2001 issue of audio xpress there was an article titled the cure for the common dynaco mkiii.
In addition, the bias circuit will now utilize two trimmers mounted on the top. Really fun to build and a hell of a good time while learning to become much more adept at understanding schematics and the overall design of the dynaco mark iiis. It was supposed to be a relatively inexpensive mod which improved the sound. Make offer dynaco mkiii mk iii mk3 mk 3 tube amplfier restoration kit. Amp is sold, but you can still find these on ebay, so be happybut buy a restored one, or take it to a tech, because you are only dreaming of plugging one of these into a wall socket, without starting a fire or having the thing blow or burn out. Mar 16, 2003 hi, the dynaco mk iv is designed to use a 7199, gz34 rectifier tube and a pair of el34 tubes. How to upgrade a dynaco mark iii a pictorial 2channel. Dynaco mkiii quad cap replacement board january 25, 1998 version 1. These have been serviced with new multi section and electrolytic caps, new solen silver metalized foil caps on the driver boards, new bias resistors and potentiometers. The second deviation would be a more modern driver board for the mk iii. Power amplifiers a variety of new and custom designs using all manner of dht and beam powerpentodes are available.
Here is a beautiful pair of dynaco mkiii mono amplifiers. A nos 5ar4, a cap board, and a choke will provide the best regulation. This board will replace the driver tube with two 6sn7, and replace the selenium rectifier with a modern silicon diode. Dynaco mark iii mono block tube ampspair mkiiidynaco.
Dynaco dynakit mkiii manual power amplifier kit hifi. Im not aware of people going to mk 3s then ditching them for something else. Last few pics show updated caps on the driver boards, and high voltage multi section. St70 baseline2 dynaco sca35 st35 tube amplifier upgrade. This dynaco mk iii sports a specially designed driver board produced in the 1980s at musical concepts. Triode electronics sds labs capacitor board for dynaco mk3, mk2 and sunn ampufiers easy installation instructions. The dynaco mark iii is the highest power amplifier that was widely sold under the dyna name. Also popular are rebuild kits with newly engineered driver boards that one can use to improve an existing st70. I solder the parts on the board where indicated see parts list for part numbers. While you can select any of the vacuum tubes presented below to complete your tube set for the dynakit mark iii amp, dynakit recommends the following. Driver boards for dynaco mark ii and mark iii triode electronics. Restoration module this is an exact replacement for the original dynaco pc3 board fabricated from milspec materials. One each of the other tubes is used per channel as a combined phase splitter driver in a longtailed pair configuration. The chassis and transformers from triode are much higher quality that from the other vendors.
The st70 used four el34 output tubes, one gz345ar4 rectifier tube, two 7199 input driver tubes, two output transformers, one power transformer. Dynaco mark iii restoration and modification hudson. All connections to the board are marked with the original number markings on the top and bottom silkscreen layers. For sale is a pair of triode electronics, dynaco mkiii driver boards, one board is fully assembled, the other board is new and unassembled. With your circuit, one of the first things i noticed was that different recordings are clearly different, indicating to me that the amplifier is neutral, rather than co. Dynaco dynakit mkii manual power amplifier kit hifi engine. The el34s will be able to handle the 15 extra volts, as well. This is for a pair of dynaco mark iii monobock amplifiers assembled from the triodelectronics kits. Dynaco dynakit markiii mk iii for sale us audio mart. Dynaco mark iv amplifier audiogon discussion forum.
Kara chaffee described a modification for the mark iii which replaced the 6an8 driver. Lets just say i used the board on a few dynaco s and i was happy with the results as compared to other mod boards and stock boards i tried. Put a set of nos tung sol 6550s gray plate no holes or black plates, nice driver tubes like a 6an8 and a mullardhammond gs 34 or 37 even better. Dynaco mkiii mods diy canuck audio mart hifi and audio forum. This driver uses the classic modified mullard topology with constant current source in the tail of the phase splitter a perfect mix of performance and. There are currently several on the market, one called the poseiden from diytube, one from tubes4hifi that incorporates additional electrolytics on the board itsself, one from curcio audio and one from triode electronics. The amps had been serviced recently elsewhere and the work done was trivial compared to what was actually needed. This board is a must for any serious restoration of the dynaco stereo70 to full stock condition. This is my attempt to document the differences between the original dynaco design of the mark iii amplifier using the 6an8 vs a new design. Therefore applying the same circuit that we developed for the stereo 70 to the mark 3 resulted in a dramatic improvement over the stock amplifier topology.
Dynaco mark iii poseidon board vs original dynaco 6ana. Dynaco mkiii triode electronics driver boards x2 for. Topologically it is really very similar to the amp board above, but with some provision for power supply atop the driver board. This is my attempt to document the differences between the original dynaco design of the mark iii amplifier using the 6an8 vs a new design diytube poseidon driver board using a 12ax7 and 12au7 or. Abj amplifier banana jack upgrade kit for the dynaco stereo 70, mark iii.
This dynaco st70 driver board pc3 has been developed and designed to be a dropin replacement for dynaco 7199 board. Our driver circuit is a modern all triode driver design, for totally neutral uncolored sound. They do look to be near original with little work done to them, the only thing i can see that has been replaced up top is the one single yellow colored cap on the circuit board per amp. The st70 used four el34 output tubes, one gz345ar4 rectifier tube, two 7199 input driver tubes, two. These have been completely updated with new quad cap power supply filtering. I have used a pair of dynaco mk iii amps in my home stereo system for over 15 years. My dynaco mkiiis are the dynakitparts version and i use the high gain tubes4hifi driver boards which use three 12at7s. The driver tubes were also relatively new zenith labeled uncarbonized 7199s, of unknown american manufacture. Thats when these things were laid out with black tape type material by the way. One half of the first tube is used for each channel as a voltage amplifier. Dynaco dynakit mkiii manual power amplifier kit hifi engine. The original dynaco board used only a single 6an8 tube with some capacitors and resistors.
Dyna mark iii amp and the sds labs quad cap board wife warming her toes on the mkiiis. Dynaco mkiii monoblock tube amplifiers curcio audio premium upgrades dynakit. Also, is it possible to use other tubes with the original desgin. Ii was sold for several years until its replacement in 1956 by the mk. All four boards make use of two driver tubes as opposed to the stock versions single tube. Triode usa tube amp kits transformers tubes dynaco.
Dynaco mark iii poseidon board vs original dynaco 6ana driver. Stereo 70 driver board 7199 board replacement modules a. Dynaco st70 6gh8 6gh8a ecf82 driver board pcb pc3 kit dyna. Dynaco vintage amplifiers and tube amps for sale ebay. In 1955, the two men founded the dyna company later dynaco with the intention of not only producing transformers, but highquality audio circuitry. They have the upgraded driver boards and cap boards. Dynaco mark iii restoration and modification hudson valley hifi. Of note however, this is an area where heathkit really shined, steering very clear of such. Diytube mark iii poseidon driver board driver board designed by shannon parks over at.
It uses a circuit of outstanding performance characteristics, along with top quality parts, including the new dynaco a430 output transformer the finest available. The triode electronics kit eliminates the superfluous holes in the chassis and makes use of a cap board inside rather than the tall quad cap, along with a different driver board. There was a nigher power amp the mark vi, but it wasnt widely available. Dynaco mkiii mono amplifiers completely restored and stunning. The capacitors in the power supply are not rated at a high enough voltage for the power. I wanted two cabinets so i could use them as pedestals for the l100s if i so chose, or stack them out of sight. This kit will change the way your tired old dynaco st70 will sound and look. Turn off your mk iii and replace the pulled rectifier tube. Dynaco dynakit mark iii tube amplifier schematic and manual. New 6sn7 octal driver use for dyna mk3, vta m125s or vta m70s the bare.
Finally realized it would have to be a 12 driver in order to keep the cabinet size reasonable. Modifications for the dynaco tm mkiii mono power amplifier. Roy just a note to let you know how much i enjoy the driver. One of these tubes has been replaced, for reasons which will be discussed further in the section on the driver board.
With the exception of replacing one tube, they have given me many hours of listening pleasure. Dynaco gold output banana jack boards st70 mkiii mkiv ebay. I ordered the boards and components as a kit and sourced the coupling capacitors from mouser. Tubes for the dynakit mark iii mono amplifier antique electronic.
With the help of bob tucker, the st70 was designed in 1959 to reduce distortion and improve audio quality with four el34 output tubes, a gz34 rectifier tube, two 7199 input driver tubes, two ultralinear output transformers and a power. Our new boards for dynaco mk4 are identical circuitwise cascode input with longtail pair phase inverter to our mk3mk2 boards, but resized to fit the mk4. Page 1 cae dynaco driver replacement module pc1u rev 2. The dynaco dynakit mark iii is a monoblock amplifier with a 6an8 input stage and a pushpull kt88 output stage. Both it and battery bias options available where appropriate. Dynaco mkiii mods diy canuck audio mart hifi and audio.
Dynaco dynakit mk iii amplifiers, serviced for sale us. Oct 06, 2015 pair of dynaco mk ii el34 6ca7 mono tube amplifiers for sale on ebay by username jimjam041 or in ebay store jimjamsvintagemusic. It follows the original wire hole layout, but it was modified to use widely available 6gh8 6gh8a 6kd8 ecf82 tubes instead of the obsolete and hard to find 7199 tubes. With the owner we decided on the new 6sn7 driver board from the guys at tubes4hifi.
All caps, resistors, and tube sockets are included to make a complete working board. Dynaco mark iii poseidon board vs original dynaco 6ana driver board duration. The irons are still good as are the original driver boards. I am still baffled by the input driver board however. Some of the driver boards were just plated copper without even silk. Our newest version includes a filament jumper allowing use of tubes with 9aj or 9lp pinout, thus allowing use of. Get the best deals on dynaco vintage amplifiers and tube amps when you shop the largest online selection at. The tubes are all new, and the power tubes are brand new genelex kt88 gold lion tubes. The basic modification consists of replacing the driver board, performing easily done minor modifications revising a few connections to the output tubes, and installing to the power. Many of my friends told me to join the 20th century when they first saw them, but i soon changed their minds after listening to my system. The dynaco dynakit mark iii amplifier is rated at 60 watts. Oct 08, 2017 dynaco mark iii mk 3 restoration part 9 final bg081 duration.
A variety of new and custom designs using all manner of dht and beam. This kit will replace the original dynaco driver circuit and printed circuit board, using the excellent sounding 6sn7 triode. Many of my friends told me to join the 20th century when they first saw them, but i. This elegant dyna mk iii upgrade was performed recently. Each amplifier requires one 12au7 plus one each of either 12au7, 12bh7, 6cg76fq7 or 6n1p. The kits i built up were the aforementioned dynaco st400 and pat 5, an early 80s heathkit tuner, the van alstine super pas iii, dyna mk iiis. Recently we had an original owner pair of dynaco mark iii amplifiers brought to us for restoration and modification.
The basic modification consists of replacing the driver board, performing easily done minor modifications revising a few connections to the output tubes, and installing to the power supply, your choice of input and output connectors. Rio is a 50 ohm, sw resistor, used rather than the choke shown on the hookup diagram notes for sunn amplifiers. This design coupled with the robust and high quality output transformers in. Does anyone have any specific details about this article. But when i put the boards in it took on a new life form. Dynaco mk 3 standard upgrade assembly, installation, and adjustment manual page 3 cae dynaco driver replacement module pc1u rev 2 iii.
Unfollow dynaco mk iv to stop getting updates on your ebay feed. I own a pair and occasionally run them to keep em alive. The board was very well laid out and a quality part. Here at dynakit you will find the right parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. Details about dynaco mkiii mk iii mk3 mk 3 tube amplfier restoration kit. Iii and pam1 preamp allowed the company to offer some new products. The dyna mkiii has a basic design flaw that none of the other dynaco products have. It is indeed very poorly made and appears quite fragile. They have new 6sn7 driver boards with individual bias, a new multisection can cap, new 3d printed binding post plates and bias test points. This a drop in replacement for the original dynaco st70 pc3 driver board but with modern epoxy fiberglass pcb.
Diytube mark iii poseidon driver board triode electronics. The original dynaco 6an8 design we believe was inferior to the 7199 driver used in the stereo 70. Introduced in 1959, the st70 was available as a kit dynakit intended for assembly by the purchaser or as a complete factorywired unit dynaco. Dynaco mkiii monoblock tube amplifiers curcio audio. Modifications for the dynaco tm mkiii mono power amplifier basic features. Building the pc board pc1u components are to be inserted on the non foil side and soldered on the foil side. One of them is missing some parts like resistors and a can cap etc. Clearly, these are superb tubes to use in a reference dynaco st70. Recently we had an original owner pair of dynaco mark iii amplifiers brought. During a visit to the new yorkbased brociner electronics the same year, hafler met an audio engineer named ed laurent, who had designed a novel singletube driver circuit for a power amplifier.
Dynaco mark iii in the march 2001 issue of audio xpress there was an article titled the cure for the common dynaco mkiii. The layout was changed to use the contemporary components and 6gh8a tubes. A custom dynaco st70 kit diy audio electronics from. I was working on the ez260, but came across 3 beat dynaco mkiii mono amplifiers. The scan below is the dynaco dynakit mark iii tube amplifier schematic from the instructions manual. Onto assembly of the triode electronics driver board. Unfollow dynaco mk iii to stop getting updates on your ebay feed. Those look to be original 196070s dynaco mark iiis to me. Biasing and balancing 1connect a voltmeter on a setting to handle up to 2vdc across either kt88 cathode 10 ohm resistor. Maybe this is a later standard dynaco driver board.